Light signal



summa D* Knaur SIGNAL.v

Filed Marck! 20, 1925 2 Sheets-Sheet 1 Y I I I I I INVENTOR BY@ im.

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Fig. 5.

Patented Oct. 30, 1928.

UNITED STATES PATENT OFFlCE.

WESLEY B. WELLS, OF WILKINSBURG. PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

LIGHT SIGNAL.

Application led March 20, 1925.

My invention relates to light signals for railways, that is, to signals of the type coinprising a source of light and optical means including an echelon lens for projecting a beam of parallel iays from such source to a distant point.

One feature of my invention is the provision of means associated with the echelon lens for projecting a portion of the rays from the light source downwardly to produce an indication to an observer close to the signal.

I will describe two forms of light signals embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a vertical sectional view showing one form of light signal embodying my invention. Fig. 2 is a front view of the central portion of bulls-eye ofthe outer lens 3 of the signal shown in Fig. 1. F ig. 3 is a vertical sectional view showing a modified form of light signal embodying my invention. Fig. 4 is an end view of a prismatic screen and supporting tube therefor forming part of the signal shown in Fig. 3.

Similar reference characters refer to similar parts in each of the views.

Referring first to Figs. 1 and2, the signal comprises a frame or housing B supporting a source of light A, which, as here shown, is an elect-rie incandescent lamp. The frame or housing B also supports a doublet C made up of two echelon lenses 2 and 3, arranged to project a beam of substantially parallel rays 9 from the lamp A to a distant point. The steps 4 of the inner lens 2 are located on the outer surface of this lens, whereas the steps 5 on the outer lens 3 are located on the inner surface of this lens. The inner lens 2 is provided with the usual bulls-eye or central lenticular portion 6, and the outer lens 3 is likewise provided with the usual bulls-eye or central lenticular portion 7.

In the form of my invention shown in Figs. 1 and 2, the inner surface of the bulls-eye T is provided with a plurality of horizontal prisms 8, which prisms are so designed as to project a portion of the rays from the lamp A downwardly and to spread these rays vertically, as indicated by the dash lines 1U. rIhese downwardly deflected iays provide an indication to an observer close to the signal.

The prisms 8, as here shown, are moulded on the inner surface of the lens 3. As far as Serial No. 17,032.

their optical features are concerned. these prisms could equally well be moulded on the outer surface ofthe lens 3. but they would then tend to collect dirt and would require frequent cleaning.

The form of my invention illustrated in Fig. 1 cannot be applied to an existing signal without replacing at least the outer lens 3 of the doublet C. To permit my invention to be applied to an existing signal without replacing this lens, the form of my invention illustrated in Figs. 3 and 4 may be used. Referring to these views, the outer lens 3 is 'of the usual form, in that the bulls-eye 7 is not provided with prisms. Interposed between the two lenses 2 and 3, however, is a prismatic screen 8a, the function of which is the same as the function of the prisms 8 in the forms illustrated in Figs. 1 and 2. This screen 8a is mounted in a frustum-shaped tube 11, the outer end of which lits into the center step 5 of the outer end of lens 3, and the inner end of which tube tits into the center step 4 of-.the inner lens 2. In order to prevent the screen 8a from turning in the tube 1l and the tube fioin turning in the lens, a plurality of strips of rubber 12 are interposed between the screen and the tube and between the tube and the outer lens 3. Then the piisniatic screen 8a is pressed into the outer end of the tube these rubber strips will be compressed and so will prevent the screen from turning in the tube. Likewise, when the tube 11 is pressed into the center step of the lens 3, these rubber strips will be compressed between the tube and the lens and so will prevent the tube from turning.

The form of my invention, illustrated in Figs. 3 and 4, has one advantage over t-lie form shown in Figs. 1 and 2, in that the prismatic screen 8a may be tuined slightly with respect to the lens, thereby throwing the close-up indication to either the right or the left of the signal, as desired, at the saine time leaving the lens 3 in its oiiginal adjusted position with respect to the frame B.

In both forms of my invention the intensity of the main or distant indication given by the. signal will be reduced approximately 15 or 20 per cent due to the downward deflection of the iays 10. One important feature of my invention, however, is the fact that the rays l0 for the close-up indication are taken from the center of the beam, so that as a train approaches the signal the main or distant indication is in the form of a circular beam at all points from which this indication is visible. In other words, the circular form of the main beam is not in any way sacriliced to provide for the close-up indication.

Although I have herein shown and described only two forms of light signals embodying my invent-ion, it is understood that various changes and modifications may be made therein within the scope or' the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. In a railway light signal comprising a source of light and a doubletpp de up ot two echelon lenses tor pidjIe-@tirigr a beam of para e rays from said source to a distant point, the combination therewith of a frustumshaped tube the large end of which fits into the center step ot' the outer lens and the small end of which tits into the center step of the inner lens. and a prismatie screen mounted in said tube for projecting a portion ot' the rays from said source downwardly to provide an indication to an observer el se tovtliesigiral,

E. In ''ilwaylightisigiial'comprising a source of light and a doublet made up ot two echelon lenses for projectingr a beam of par* allel rays from said source to a distant point, the combination therewith of a frustumshaped tube the large end of which tits into the center step of the outer lens and the small end of which fits into the center step of the echelon lenses for pr'ojecting a beam of parlleI-razs'iii said source to a distant point. the combination therewith of a tube located between and supported by said lenses, and a prismatic screen mounted in said tube for projecting a portion of the rays from said source downwardly to provide an indication to an observer close to the signal.

sl. In a railway light signal comprising a source of light and a doublet made up of two echelon lenses for projecting a beam of parallel rays from said source to a distant point, the steps on the inner lens being on the outer surface thereof and the steps on the outer lens being on the inner surface thereof, the. combination with the foregoing elements, of a tube one end of which tits into the center step of the inner lens and the other end ot which fits into the center step of the outer lens, and a prismatic screen mounted in said tube for projecting a portion of the rays from said source downwardly to provide an indication to an observer close to the signal.

In testimony whereof I aiiix my signature.

WESLEY B. WELLS. 

